C2-symmetric bisamidines: chiral Brønsted bases catalysing the Diels-Alder reaction of anthrones.
C(2)-symmetric bisamidines 8 have been tested as chiral Brønsted bases in the Diels-Alder reaction of anthrones and N-substituted maleimides. High yields of cycloadducts and significant asymmetric inductions up to 76% ee are accessible. The proposed mechanism involves proton transfer between anthrone and bisamidine, association of the resulting ions and finally a cycloaddition step stereoselectively controlled by the chiral ion pair.
Akalay
Deniz
D
Johann Wolfgang Goethe University Frankfurt, Institute of Organic Chemistry and Chemical Biology, Max-von-Laue-Str. 7, D-60438 Frankfurt am Main, Germany.
Dürner
Gerd
G
Bats
Jan W
JW
Göbel
Michael W
MW